There's the old Roman Black method. Sounds are rather hissy, but you can embed it into a pic chip. A ricochet sound mightbe well suited for it, since it might over ride the hiss.

Here's some code with number example. And a wave file you can play for getting an idea of the "quality". Not great, but you can easily tell what numbers they are.
http://www.picbasic.co.uk/forum/show...0131#post90131

and Darrel's better example:
http://www.picbasic.co.uk/forum/show...1089#post51089

(In fact, his example has a sort of laser gun sound in it.)